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  • 301.
    Bigler, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gälman, Veronika
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Numerical simulations suggest that counting sums and taxonomic resolution of diatom analyses to determine IPS pollution and ACID acidity indices can be reduced2010In: Journal of Applied Phycology, ISSN 0921-8971, E-ISSN 1573-5176, Vol. 22, no 5, p. 541-548Article in journal (Refereed)
    Abstract [en]

    Implementation of the European Union Water Framework Directive and associated national guidelines has emphasized the value of using biota, such as epilithic diatoms in streams, as indicators of water quality. However, guidelines for evaluating diatom samples have been established without explicitly evaluating their statistical robustness. We used epilithic diatom samples from 73 streams in northern Sweden and simulated the effects of variations in the counting sum size and taxonomic resolution of classifications for two indices indicating pollution (Indice de Polluo-sensibilité Spécifique, IPS) and acidity (acidity index for diatoms, ACID). Instead of the stipulated 400, we found that a count sum of 40 diatom valves for 50 streams, and 80 valves for 60 streams, would have been sufficient to obtain the same IPS index classification. The ACID index is more sensitive to count sum reductions, since the same classification would only have been obtained for 12 streams with 40 counted diatom valves or 24 streams with a count of 80 valves. Excluding rare taxa had negligible effects on the IPS and ACID indices. Excluding taxa occurring with less than 1.0% frequency affected the IPS classification of only one stream, and excluding taxa with less than 2.5% and 5.0% frequencies affected those of just one and no streams, respectively. The ACID index was affected for none, five, and 12 streams, respectively. At least in relatively unpolluted regions such as northern Sweden, our simulations suggest that a simplified methodological approach with site-specific counting sum sizes and reduced taxonomical resolution could be adopted, taking into account the way sites are classified in relation to established class boundaries. The simplified method is a step forward in improving the cost efficiency for stream monitoring, as costs of diatom analysis to obtain identical IPS and ACID classifications of our streams could be reduced considerably. Before the simplified method can be widely adopted, further simulations including regions with a higher proportion of polluted streams are required.

  • 302.
    Bigler, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Heiri, O
    Krskova, R
    Lotter, A F
    Sturm, M
    Distribution of diatoms, chironomids and cladocera in surface sediments of thirty mountain lakes in south-eastern Switzerland2006In: Aquatic Sciences, Vol. 68, p. 154-171Article in journal (Refereed)
  • 303.
    Bindler , Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Renberg , Ingemar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Rydberg , Johan
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Andrén , T
    Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy2009Article in journal (Refereed)
    Abstract [en]

    Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren ­ Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th­18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.

  • 304.
    Bindler, R
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Mired in the past – looking to the future: geochemistry of peat and the analysis of past environmental changes2006In: Global and Planetary Change, Vol. 53, p. 209-221Article in journal (Refereed)
  • 305.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Comment on "The biosphere: A homogeniser of Pb-isotope signals" by C. Reimann, B. Flem, A. Arnoldussen, P. Englmaier, T.E. Finne, F. Koller and Ø. Nordgulen2008In: Applied Geochemistry, Vol. 23, no 8, p. 2519-2526Article in journal (Refereed)
    Abstract [en]

    The paper by Reimann et al. (2008) is an echo of the debate carried out mainly by Clair Patterson and Robert Kehoe in the 1960s to 1980s about whether the enrichment of Pb in the biosphere and humans was a result of the global Pb contamination or due to natural causes and what impacts on human health were entailed ([Needleman, 1998] and [Nriagu, 1998]). Reimann et al. are also re-awakening the idea that the ‘plant pump’ is the reason for the surface enrichment of Pb in the soil (Goldschmidt, 1937). So is it time to revive this debate again? Are there reasons to expect that the enrichment of Pb and the change in Pb isotopic composition in surface soils is due to natural plant cycling and not due to the 1000-fold enrichment of Pb in the environment and humans since pristine times as originally suggested by Clair Patterson ([Patterson, 1965] and Settle and Patterson, 1980 D. Settle and C.C. Patterson, Lead in Albacore: guide to lead pollution in Americans, Science 207 (1980), pp. 1167–1176. View Record in Scopus | Cited By in Scopus (97)[Settle and Patterson, 1980])? Is it so that a changed plant uptake can explain the >90% reduction of Pb in mosses seen all over Europe since the 1970s, which co-occurs with reduced atmospheric emissions (e.g., [Berg and Steinnes, 1997a] and [Rühling and Tyler, 2001])? Is there a reason to believe that plants, independent of the geological matrix below choose to take up Pb with an isotopic composition that causes the surface organic layer all over Europe to have lower (i.e., heavier) 206Pb/207Pb ratios that are coincidentally similar to anthropogenic Pb sources? No, of course not. In this comment the author explains why he thinks future studies should not adopt the conclusions of Reimann et al.

  • 306.
    Bindler, Richard
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden.2011In: Environmental Geochemistry and Health, ISSN 0269-4042, E-ISSN 1573-2983, Vol. 33, no 4, p. 311-329Article in journal (Refereed)
    Abstract [en]

    Clair Patterson and colleagues demonstrated already four decades ago that the lead cycle was greatly altered on a global scale by humans. Moreover, this change occurred long before the implementation of monitoring programs designed to study lead and other trace metals. Patterson and colleagues also developed stable lead isotope analyses as a tool to differentiate between natural and pollution-derived lead. Since then, stable isotope analyses of sediment, peat, herbaria collections, soils, and forest plants have given us new insights into lead biogeochemical cycling in space and time. Three important conclusions from our studies of lead in the Swedish environment conducted over the past 15 years, which are well supported by extensive results from elsewhere in Europe and in North America, are: (1) lead deposition rates at sites removed from major point sources during the twentieth century were about 1,000 times higher than natural background deposition rates a few thousand years ago (~10 mg Pb m(-2) year(-1) vs. 0.01 mg Pb m(-2) year(-1)), and even today (~1 mg Pb m(-2) year(-1)) are still almost 100 times greater than natural rates. This increase from natural background to maximum fluxes is similar to estimated changes in body burdens of lead from ancient times to the twentieth century. (2) Stable lead isotopes ((206)Pb/(207)Pb ratios shown in this paper) are an effective tool to distinguish anthropogenic lead from the natural lead present in sediments, peat, and soils for both the majority of sites receiving diffuse inputs from long range and regional sources and for sites in close proximity to point sources. In sediments >3,500 years and in the parent soil material of the C-horizon, (206)Pb/(207)Pb ratios are higher, 1.3 to >2.0, whereas pollution sources and surface soils and peat have lower ratios that have been in the range 1.14-1.18. (3) Using stable lead isotopes, we have estimated that in southern Sweden the cumulative anthropogenic burden of atmospherically deposited lead is ~2-5 g Pb m(-2) and ~1 g Pb m(-2) in the "pristine" north. Half of this cumulative total was deposited before industrialization. (4) In the vicinity of the Rönnskär smelter in northern Sweden, a major point source during the twentieth century, there is an isotopic pattern that deviates from the general trends elsewhere, reflecting the particular history of ore usage at Rönnskär, which further demonstrates the chronological record of lead loading recorded in peat and in soil mor horizons.

  • 307.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Cortizas, Antonio Martínez
    Blaauw, Maarten
    Comment on "Atmospheric mercury accumulation rates between 5900 and 800 calibrated years BP in the high arctic of Canada recorded by peat hummocks" (multiple letters)2005In: Environ Sci Technol, ISSN 0013-936X, Vol. 39, no 3, p. 908-9; author reply 910Article in journal (Refereed)
  • 308.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Karlsson, Jon
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rydberg, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Karlsson, Björn
    Berg Nilsson, Lena
    Biester, Harald
    Segerström, Ulf
    Copper-ore mining in Sweden since the pre-Roman Iron Age: lake-sediment evidence of human activities at the Garpenberg ore field since 375 BCE2017In: Journal of Archaeological Science: Reports, ISSN 2352-409X, E-ISSN 2001-1199, Vol. 12, p. 99-108Article in journal (Refereed)
    Abstract [en]

    Historical documents, archaeological evidence and lake-sediment records indicate thus far that significant mining of iron and copper ores in the Berglsagen mining region in central Sweden did not begin until the late 12th century -first with iron in Norberg - and thereafter spreading rapidly throughout the region during the 13th century when also copper was included (e.g. Falun). Prior to this, iron was produced domestically from secondary sources such as bog iron, while geochemical analyses of bronze artefacts indicate copper was imported. The parish of Garpenberg was at the intersection between historical iron-and copper-mining districts, and consequently we expected our sediment record from the lake Gruvsjon ('mine lake') to follow the established 13th century development. However, a 2-3-fold enrichment in copper and lead occurred already during 375-175 BCE (pre-Roman Iron Age), together with small increases in zinc, magnesium and charcoal particles, and changes in pollen. Together these indicate a clear pattern of human disturbance connected with the ore body bordering the lake. A second distinct phase occurred 115-275 CE, but with an 8-9-fold increase in copper and lead along with other indicators. From 400 CE a permanent increase in copper and lead occurred, which then accelerated from the 13th century as seen elsewhere in the region. Our results push back the evidence for early ore mining in Sweden from the Middle Ages to the pre-Roman Iron Age. 

  • 309.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Beyond the peat: synthesizing peat, lake sediments and soils in studies of the Swedish environment2006In: Peatlands: basin evolution and depository of records on global environmental and climatic changes / [ed] I.P. Martini, A. Martínez Cortizas and W. Chesworth, Elsevier, 2006, p. 431-448Chapter in book (Other academic)
    Abstract [en]

    This chapter illustrates on comparing peat and lake sediment records and linking the quantitative record of metals in peat to contemporary environmental problems. Quantifying metal records in peat has been an important step, but new research needs to move beyond this and consider how to apply these data. Lead analyses, including stable isotopes, are now fairly routine and based on these analyses the historical trends of lead deposition are now well established in peat, lake sediments and even glacial ice. The biogeochemical cycling of lead has also been well researched, which allows making this link between the historical lead record and soil biogeochemistry. Because peat and lake sediments seem to record the same changes in mercury deposition, there is similar promise in linking the long-term peat record of mercury and other metals with biogeochemical cycling of mercury and other important metals in forests and soils.

  • 310.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Reply to comment by William Shotyk on "Does within-bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden"2006In: Global Biogeochemical Cycles, Vol. 20Article in journal (Refereed)
  • 311.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Klarqvist, M
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Förster, J
    Does within-bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden2004In: Global Biogeochemical Cycles, Vol. 18Article in journal (Refereed)
  • 312.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Korsman, Tom
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Högberg, Peter
    Swedish Univ Agr Sci, Dept Forest Ecol, Umeå, Sweden.
    Pre-industrial atmospheric pollution: Was it important for the pH of acid-sensitive Swedish lakes?2002In: Ambio, ISSN 0044-7447, Vol. 31, no 6, p. 460-465Article in journal (Refereed)
    Abstract [en]

    Acid rain has caused extensive surface water acidification in Sweden since the mid-20(th) century. Sulfur emissions from fossil-fuel burning and metal production were the main sources of acid deposition. In the public consciousness acid deposition is strongly associated with the industrial period, in particular the last 50 years. However, studies of lake-water pH development and atmospheric pollution, based on analyses of lake sediment deposits, have shown the importance of a long-term perspective. Here, we present a conceptual argument, using the sediment record, that large-scale atmospheric acid deposition has impacted the environment since at least Medieval times. Sulfur sources were the pre-industrial mining and metal industries that produced silver, lead and other metals from sulfide ores. This early excess sulfur deposition in southern Sweden did not cause surface water acidification; on the contrary, it contributed to alkalization, i.e. increased pH and productivity of the lakes. Suggested mechanisms are that the excess sulfur caused enhanced cation exchange in catchment soils, and that it altered iron-phosphorus cycling in the lakes, which released phosphorus and increased lake productivity

  • 313.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Myrstener, Erik
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Liu, Enfeng
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hansson, Sophia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Meyer-Jacob, Carsten
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mighall, Tim
    Ninnes, Sofia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rydberg, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Reshaping the landscape: mining, metallurgy and a millennium of environmental changes in south-central SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    Before the recognition of emerging environmental issues during the 20th century such as acid rain, mercury pollution, climate change and biodiversity loss, human activities had already significantly altered landscapes around the globe. As elsewhere in Europe, the introduction of agriculture into Sweden during the Bronze and Iron Ages led to changes in forest cover, especially in southern areas, but also more limited impacts in central and northern Sweden along river valleys and coastal areas. In central Sweden the rise and rapid spread of ore mining and metallurgy from the 12th and especially 13th century initiated a widespread reshaping of the landscape named after its mining heritage –Bergslagen (mining laws). This mineral rich 89,000 km2 region encompasses ~5000 metallurgical sites (furnaces, smelters, foundries, forges) and ~10000 mines registered in the Swedish National Antiquities Board’s database.

    Analyses of >30 lake-sediment records using a combination of geochemical, diatom and pollen analyses, in combination with archaeological and historical records and toponyms, add important details to the early, poorly documented history of mining/metallurgy as well as provide insights into some of the environmental impacts across this large landscape. These impacts included damming of lakes and regulation of watercourses for waterpower, increase in erosion, emission of metals to surface waters and the atmosphere (and leaching from slag piles), decrease in forest cover and changes in water quality. The discontinuous appearance of pollen from cultivated plants (cereals) indicates some limited settlement before the 12th century, but the regular occurrence thereafter of cereal pollen together with a sharp increase in charcoal particles and geochemical evidence of mining/metallurgical activities, indicates mining/metallurgy was a driving force for settlement. Decline in forest cover was gradual from the 13th century, but was more significant from the late 16th century when iron and copper production increased exponentially. The increased demand for charcoal and increased agriculture, including an expansion of summer forest farms, contributed to a reduction in inferred forest cover to 40–80% – as compared to pre-anthropogenic (≤2000 BP) values of 84–95%. From the 16th century charcoal became the limiting resource within Bergslagen and metallurgy expanded to regions adjoining Bergslagen, contributing to a more widespread decline in forest cover also beyond the Bergslagen landscape.

    In association with the increase in land-use activities and resulting changes in vegetation cover, there was a decline (20–50%) in spectrally inferred lake-water total organic carbon, which we hypothesize resulted from a decreased pool of labile soil carbon. In some lakes closely connected with blast furnaces, where the peasant-miners also lived and farmed, there was an increase in diatom-inferred lake-water pH – as observed previously in SW Sweden in association with Iron Age land use. Only in a suite of lakes in close proximity to the smelting of copper sulfide ores in the surroundings of Falun was there evidence for pre-20th century acidification.

    While current rates of environmental change may be unprecedented, they build on an already modified landscape. Because pre-industrial conditions, i.e., pre-19th century, are often used as a reference level the scale of current changes may underestimate the full extent of ecosystem and environmental impacts.

  • 314.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Bridging the gap between ancient metal pollution and contemporary biogeochemistry2008In: Journal of Paleolimnology, Vol. 40, no 3, p. 755-770Article in journal (Refereed)
    Abstract [en]

    Paleolimnology provides long-term data that are often essential for understanding the current state of the environment. Even though there is great potential, paleolimnology is rarely used together with process-related studies to solve issues regarding cycling of elements in the environment. Clearly, this is a drawback because the cycling of many elements, which cause great concern in the present-day environment, was altered long before the advent of monitoring programs. The pioneering work of C.C. Patterson and his colleagues emphasized the importance of a long-term perspective for understanding the current cycling of metals, with a focus on lead, and in particular for estimating background concentrations and human-related impacts in the environment. In Sweden the first traces of atmospheric lead pollution are found in lake sediments dated to about 3500 years ago. The long-term changes in the pollution lead record in lake sediments led us to consider how lead biogeochemistry has changed over time in response to this historical deposition‹where has this lead gone, and how much does this lead contribute to the present-day biogeochemical cycling of lead? How was lead distributed in Œpre-industrial¹ soils or more properly in natural soils not impacted by atmospheric pollution? There are many studies that have examined the effects of increased metal concentrations on soil biota, but what are the appropriate background conditions for comparison? Using lake sediments as our foundation we have analyzed lead, including its stable isotopes, in other environmental compartments, including peat, soil, and a range of boreal forest plant species, to develop a better understanding of the fate of lead derived from long-term pollution. Three important conclusions from our studies in Sweden are: (1) atmospheric lead deposition rates during the 20th century were 100 to as much as 1000 times higher than natural deposition rates a few thousand years ago. Even with stricter emission standards during the past three decades and the resultant reductions in deposition, lead deposition rates today are still 10­100 times greater than natural rates. This increase in deposition rates modeled from sediment and peat records is of a similar scale to estimated changes in body burdens of lead in modern versus ancient humans. (2) In Europe about half of the cumulative burden of atmospherically deposited lead was deposited before industrialization. In southern Sweden the cumulative burden of pollution lead during the past 3500 years is 2­5 g Pb m-2 and in the Œpristine¹ northern parts of the country there is about 1 g Pb m-2. (3) Predicted recovery rates for soils are slow; in the cold climate of Scandinavia, we find that the soil surface (O horizon), where most soil biota reside, retains lead deposited over the past 150­500 years. Therefore, although lead deposition rates in Europe, as well as N. America, are only 10% of those a few decades ago, it will take several decades or longer for lead concentrations in soils to respond appreciably. The slow turnover rates for lead in the environment and gradual immobilization of lead in deeper soil mineral horizons also inhibits a loss of lead to surface waters in areas removed from point sources.

  • 315.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Emteryd, Ove
    Tree rings as Pb pollution archives? A comparison of 206Pb/207Pb isotope ratios in pine and other environmental media.2004In: Sci Total Environ, ISSN 0048-9697, Vol. 319, no 1-3, p. 173-83Article in journal (Refereed)
  • 316.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rydberg, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Revisiting Key Sedimentary Archives Yields Evidence Of A Rapid Onset Of Mining In The Mid-13th Century At The Great Copper Mountain, Falun, Sweden2016In: Archaeometry, ISSN 0003-813X, E-ISSN 1475-4754, Vol. 58, no 4, p. 642-658Article in journal (Refereed)
    Abstract [en]

    Mining in Falun, Sweden, was first mentioned in a deed from AD 1288, but previous studies of peat and lake sediments inferred that mining began during the fifth to eighth centuries. In order to reassess these findings, we performed new geochemical analyses on new samples from three key sites: Tisksjobergets myr, a buried mire alongside the mine; Tisken, a small lake in Falun; and Runn, the main recipient for waters draining through Falun. At Tisksjobergets myr, the peat contains up to 6% copper, giving it the characteristics of a cupriferous bog. Hence, this record is not useful for tracing early mining. The sediments of Tisken-upon which many of the old interpretations have relied-contain numerous cut wood fragments, and two of those gave young and reversed radiocarbon dates (19th and 16th centuries for 192 and 187 cm, respectively). This indicates that the sediment was derived from infilling and, thus, has little value as a historical record. Runn's sediment-the only reliable record-provides clear evidence of a rapid onset of large-scale mining from c. AD 1245, with abrupt increases in ore-related elements-for example, a 34-fold increase in copper-this increase is consistent with the mid-13th century burial of the mire at Tisksjoberget.

  • 317.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rydberg, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Establishing natural sediment reference conditions for metals and the legacy of long-range and local pollution on lakes in Europe2011In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 45, no 4, p. 519-531Article in journal (Refereed)
    Abstract [en]

    The intention of the European Water Framework Directive (WFD) and the national guidelines that implement the WFD is that present-day conditions and future management strategies are to be based on an understanding of reference conditions for the particular water body of interest. In the context of non-synthetic pollutants such as lead, mercury and cadmium, the criteria for a high ecological status are that "concentrations [are] within the range normally associated with undisturbed conditions". How this normal range is to be defined is open to interpretation; for example, in Sweden reference conditions based on sediment records are defined as the conditions prior to modern industrialization, i.e. prior to the mid-1800's. These pre-industrial reference conditions would correspond to sediments 15-30 cm depth. However, 'reference conditions' are not always synonymous with 'natural background conditions'. Analyses of long sediment profiles from Swedish lakes and from a few other areas, however, have shown that pre-industrial pollution-at least with regard to lead-was extensive. Atmospheric lead pollution has its origin in antiquity, with a small, well-defined peak already during the Greek-Roman period 2,000 years ago. Sediments deposited 300-500 years in Sweden and Scotland, for example, show a dominance of pollution lead, and in some sediment records also cadmium and copper pollution was extensive. Thus, in order to characterize natural background concentrations of metals, long sediment profiles are needed to reach sediments unaffected by pollution (> 3,000 years BP); this can correspond to sediments below 50 cm in some lakes, but in others sediments below 300 cm or more.

  • 318.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Segerström, Ulf
    Pettersson-Jensen, Ing-Marie
    Berg, Anna
    Hansson, Sophia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Holmström, Harald
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Olsson, Karin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Early medieval origins of iron mining and settlement in central Sweden: multiproxy analysis of sediment and peat records from the Norberg mining district2011In: Journal of Archaeological Science, ISSN 0305-4403, E-ISSN 1095-9238, Vol. 38, no 2, p. 291-300Article in journal (Refereed)
    Abstract [en]

    The historical Norberg mining district in central Sweden with its shallow, easily accessible iron ores figures prominently in the earliest documents from the 14th century concerning mining or metallurgy. This 1000-km2 district is considered to be one of the first areas in Sweden exploited for iron ores and, in fact, Europe’s oldest known blast furnace, Lapphyttan, is located in the Norberg district about 10 km from the mines in the village of Norberg (Norbergsby). Earlier archaeological excavations suggest the furnace was in operation as early as the 11th or 12th century (870 and 930 14C yr BP), and a number of other sites in the district have been dated to the 13th–15th centuries. Here, we have analyzed two lake sediment records (Kalven and Noren) from the village of Norberg and a peat record from Lapphyttan. The Lapphyttan peat record was radiocarbon dated, whereas the sediment from Kalven is annually laminated, which provides a fairly precise chronology. Our pollen data indicate that land use in the area began gradually as forest grazing by at least c. AD 1050, with indications of more widespread forest disturbance and cultivation from c. 1180 at Lapphyttan and 1250 at Kalven. Based on 206Pb/207Pb isotope ratios in Kalven’s varved sediment record, there is an indication of mining or metallurgy in the area c. 960, but likely not in immediate connection to our sites. Evidence of mining and metallurgy increases gradually from c. 1180 when there is a decline in 206Pb/207Pb ratios and an increase in charcoal particles at Lapphyttan, followed by increasing inputs of lithogenic elements in Noren’s sediment record indicating soil disturbance, which we attribute to the onset of mining the iron ore bodies surrounding Noren. From AD 1295 onwards evidence of mining and metallurgy are ubiquitous, and activities accelerate especially during the late 15th century; the maximum influence of Bergslagen ore lead (i.e., the minimum in 206Pb/207Pb isotope ratios) in both Kalven and Noren occurs c. 1490–1500, when also varve properties change in Kalven and in Noren sharp increases occur in the concentrations of a range of other ore-related metals (e.g., arsenic, cadmium, copper, iron, lead, mercury and zinc). From the 15th century onwards mining and metallurgy are the dominant feature of the sediment records.

  • 319.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Wik-Persson, M.
    Renberg, Ingemar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Landscape-scale patterns of sediment sulfur accumulation in Swedish lakes2008In: Journal of Paleolimnology, Vol. 39, p. 61-70Article in journal (Refereed)
    Abstract [en]

    Sulfur has played a central role in the acidification of many lakes in Scandinavia and other regions. As part of the research into sulfur cycling, numerous studies have analyzed the sediment record in order to develop insights into past in-lake cycling of sulfur, particularly in the context of reconstructing past deposition rates. Although many of these studies have shown that it is not easy to interpret the sediment record in terms of past sulfur deposition rates, analyses of sulfur in sediment still provide valuable information on the response of lakes to anthropogenic sulfur deposition. Here, we have analyzed sulfur in top and bottom samples from short surface cores (25-35 cm, representing >= 250 years) as well as bulk cores from similar to 110 lakes located throughout Sweden, which were collected during 1986, as well as in more-detailed profiles from six lakes. The lakes with the highest surface sediment concentrations (9-24 mg S g(-1) dry mass) and the highest calculated inventories of 'excess' sulfur (20-180 g S m(-2)) are found in southern Sweden and around one industrial area along the northeastern coast where sulfur deposition rates and lake-water concentrations have been highest. For many lakes in the central and northern inland region it is common that the sediment cores exhibit either no enrichment or even a decline in sulfur concentrations in near-surface sediments, which we suggest was the pre-pollution norm for lakes. Although interpreting sulfur sediment profiles is problematic for reconstructing deposition, a more-comprehensive spatial sampling approach shows that there is a good geographic agreement between sulfur deposition, lake-water chemistry and sediment sulfur accumulation.

  • 320.
    Bindler, Richard
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Yu, Ruilian
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. College of Chemical Engineering, Huaqiao University, Xiamen, Fujian 361021, P.R. China.
    Hansson, Sophia
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Classen, Neele
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Karlsson, Jon
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Mining, Metallurgy and the Historical Origin of Mercury Pollution in Lakes and Watercourses in Central Sweden2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 15, p. 7984-7991Article in journal (Refereed)
    Abstract [en]

    In Central Sweden an estimated 80% of the lakes contain fish exceeding health guidelines for mercury. This area overlaps extensively with the Bergslagen ore region, where intensive mining of iron ores and massive sulfide ores occurred over the past millennium. Although only a few mines still operate today, thousands of mineral occurrences and mining sites are documented in the region. Here, we present data on long-term mercury pollution in 16 sediment records from 15 lakes, which indicate that direct release of mercury to lakes and watercourses was already significant prior to industrialization (<AD 1800). Thirteen of our lakes show increases in mercury from 3-fold-equivalent to the enrichment factor in many remote lakes today-to as much as 60-fold already during the period AD 1500-1800, with the highest values in the three lakes most closely connected to major mines. Although the timing and magnitude of the historical increases in mercury are heterogeneous among lakes, the data provide unambiguous evidence for an incidental release of mercury along with other mining metals to lakes and watercourses, which suggests that the present-day problem of elevated mercury concentrations in the Bergslagen region can trace its roots back to historical mining.

  • 321. Bishop, K.
    et al.
    Buffam, I.
    Erlandsson, M.
    Fölster, J.
    Laudon, Hjalmar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Seibert, J.
    Temnerud, J.
    Aqua Incognita: the unknown headwaters2008In: Hydological Processes, Vol. 22, p. 1239–1242-Article in journal (Refereed)
    Abstract [en]

    Running water comprises just over one millionth of the world’s water. The importance of those streams and rivers as a resource for human welfare and biodiversity, however, is far out of proportion to that minuscule fraction. This explains why protecting running waters (the flow regimes, water quality and biota) is such a vital concern for society. Yet for all the focus and concern, how much do we actually know about these running waters, and the lotic habitat they comprise?

  • 322. Bishop, K
    et al.
    Rapp, L
    Köhler, S
    Korsman, Tom
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Testing the steady-state water chemistry model predictions of pre-industrial lake pH with paleolimnological data from northern Sweden.2008In: Sci Total Environ, ISSN 0048-9697, Vol. 407, no 1, p. 723-9Article in journal (Refereed)
    Abstract [en]

    Criteria are needed for distinguishing naturally acid water from that acidified by air pollution, especially in the organic-rich waters of northern Sweden. The Steady-State Water Chemistry Model (SSWC) was augmented to include organic acidity so that it could predict pre-industrial pH in organic-rich waters. The resulting model predictions of preindustrial ANC and pH were then tested against diatom predictions of pre-industrial pH and alkalinity in 58 lakes from N. Sweden (after alkalinity was converted to ANC using the CBALK method). The SSWC Model's predictions of pre-industrial lake pH in N. Sweden did not correspond well with the diatom predictions, even when accounting for the uncertainty in the diatom model. This was due to the SSWC's sensitivity to short-term fluctuations in contemporary water chemistry. Thus the SSWC Model is not suitable for judging the acidification of individual lakes in areas such as northern Sweden where the degree of chronic acidification is small, or without a good average value of contemporary water chemistry. These results should be considered when assessing the accuracy of critical loads calculated using SSWC.

  • 323. Bishop, K
    et al.
    Seibert, J
    Köhler, S
    Laudon, H
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Resolving the Double Paradox of rapidly mobilized old water with highly variable responses in runoff chemistry2004In: Hydrological Processes, Vol. 18, p. 185-189Article in journal (Refereed)
  • 324. Bistrom, Olof
    et al.
    Nilsson, Anders N.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bergsten, Johannes
    Taxonomic revision of Afrotropical Laccophilus Leach, 1815 (Coleoptera, Dytiscidae)2015In: ZooKeys, ISSN 1313-2989, E-ISSN 1313-2970, no 542, p. 1-379Article in journal (Refereed)
    Abstract [en]

    The African species of the genus Laccophilus Leach, 1815, are revised, on the basis of study of adult specimens. In all, 105 species are now recognized. A phenetic character-analysis was undertaken, which resulted in a split of the genus into 17 species groups. Diagnoses and a description of each species are given together with keys for identification of species groups and species. We also provide habitus photos, illustration of male genitalia and distribution maps for all species. New species are described as follows: L. grossus sp. n. (Angola, Namibia), L. rocchii sp. n. (Tanzania, Namibia, Botswana, Mozambique), L. ferrugo sp. n. (Mozambique), L. furthi sp. n. (Madagascar), L. isamberti sp. n. (Madagascar), L. inobservatus sp. n. (Gambia, Senegal, Mali, Niger, Sudan, Chad, Ethiopia, Burkina Faso, Ivory Coast, Ghana, Nigeria, Cameroon, Zaire and Asia: Yemen), L. cryptos sp. n. (Zaire, Mozambique, Zimbabwe, Namibia, Botswana, South Africa), L. enigmaticus sp. n. (Nigeria, Sudan), L. bellus sp. n. (Benin, Nigeria), L. guentheri sp. n. (Guinea, Ghana), L. guineensis sp. n. (Guinea), L. decorosus sp. n. (Uganda), L. empheres sp. n. (Kenya), L. inconstans sp. n. (Guinea, Ivory Coast, Ghana, Nigeria, Cameroon), L. brancuccii sp. n. (Central African Republic), L. incomptus sp. n. (Cameroon), L. australis sp. n. (Tanzania, South Africa), L. minimus sp. n. (Namibia), L. eboris sp. n. (Ivory Coast), L. insularum sp. n. (Madagascar), L. occidentalis sp. n. (Gambia, Senegal, Mali, Guinea, Sierra Leone, Ivory Coast, Ghana, Benin, Nigeria, Central African Republic, Zaire) and L. transversovittatus sp. n. (Madagascar). L. restrictus Sharp, 1882, is restored as good species; not junior synonym of L. pictipennis Sharp, 1882. New synonyms are established as follows: L. continentalis Gschwendtner, 1935 = L. perplexus Omer- Cooper, 1970, syn. n., L. taeniolatus Regimbart, 1889 = L. congener Omer-Cooper, 1957, syn. n., L. adspersus Boheman, 1848 = L. vitshumbii Guignot, 1959, syn. n. = L. adspersus nigeriensis Omer-Cooper, 1970, syn. n. = L. adspersus sudanensis Omer-Cooper, 1970, syn. n., L. modestus Regimbart, 1895 = L. espanyoli Hernando, 1990, syn. n., L. flaveolus Regimbart, 1906 = L. pampinatus Guignot, 1941, syn. n., L. trilineola Regimbart, 1889 = L. simulator Omer-Cooper, 1958, syn. n., L. mediocris Guignot, 1952 = L. meii Rocchi, 2000, syn. n., L. epinephes Guignot, 1955 = L. castaneus Guignot, 1956, syn. n., L. saegeri Guignot, 1958 = L. comoensis Pederzani & Reintjes, 2002, syn. n., L. restrictus Sharp, 1882 = L. evanescens Regimbart, 1895, syn. n., L. incrassatus Gschwendtner, 1933 = L. virgatus Guignot, 1953, syn. n., L. cyclopis Sharp, 1882 = L. shephardi Omer-Cooper, 1965, syn. n., L. burgeoni Gschwendtner, 1930 = L. wittei Guignot, 1952, syn. n., L. secundus Regimbart, 1895 = L. torquatus Guignot, 1956, syn. n., L. desintegratus Regimbart, 1895 = L. sanguinosus Regimbart, 1895, syn. n. and L. flavopictus Regimbart, 1889 = L. bergeri Guignot, 1953, syn. n. = L. segmentatus Omer-Cooper, 1957, syn. n. Lectotypes are designated for the following taxa: L. productus Regimbart, 1906, L. ruficollis Zimmermann, 1919, L. sordidus Sharp, 1882, L. alluaudi Regimbart, 1899, L. pictipennis Sharp, 1882, L. wehnckei Sharp, 1882, L. continentalis Gschwendtner, 1935, L. simplicistriatus Gschwendtner, 1932, L. complicatus Sharp, 1882, L. rivulosus Klug, 1833, L. ampliatus Regimbart, 1895, L. pilitarsis Regimbart, 1906, L. adspersus Boheman, 1848, L. livens Regimbart, 1895, L. modestus Regimbart, 1895, L. nodieri Regimbart, 1895, L. flaveolus Regimbart, 1906, L. pallescens Regimbart, 1903, L. restrictus Sharp, 1882, L. vermiculosus Gerstaecker, 1867, L. mocquerysi Regimbart, 1895, L. bizonatus Regimbart, 1895, L. tschoffeni Regimbart, 1895, L. persimilis Regimbart, 1895, L. poecilus Klug, 1834, L. lateralis Sharp, 1882, L. lateralis var. polygrammus Regimbart, 1903, L. cyclopis Sharp, 1882, L. shephardi Omer-Cooper, 1965, L. conjunctus Guignot, 1950, L. grammicus Sharp, 1882, L. flavoscriptus Regimbart, 1895, L. flavosignatus Regimbart, 1895, L. brevicollis Sharp, 1882, L. secundus Regimbart, L. desintegratus Regimbart, 1895, L. gutticollis Regimbart, 1895, L. luctuosus Sharp, 1882 and L. inornatus Zimmermann, 1926. Laccophilus remex Guignot, 1952, comprises a species complex with uncertain taxonomic delimitation; the complex includes L. concisus Guignot, 1953, L. turneri Omer-Cooper, 1957 and L. praeteritus Omer-Cooper, 1957, as tentative synonyms of L. remex Guignot, 1952.

  • 325. Bjorck, S
    et al.
    Bennike, O
    Rosén, P
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Andresen, C S
    Bohncke, S
    Kaas, E
    Conley, D
    Anomalously mild Younger Dryas summer conditions in southern Greenland2002In: Geology, ISSN 0091-7613, E-ISSN 1943-2682, Vol. 30, no 5, p. 427-430Article in journal (Refereed)
    Abstract [en]

    The first late-glacial lake sediments found in Greenland were analyzed with respect to a variety of environmental variables. The analyzed sequence covers the time span between 14400 and 10500 calendar yr B.P., and the data imply that the conditions in southernmost Greenland during the Younger Dryas stadial, 12800-11550 calendar yr B.P., were characterized by an arid climate with cold winters and mild summers, preceded by humid conditions with cooler summers. Climate models imply that such an anomaly may be explained by local climatic phenomenon caused by high insolation and Fohn effects. It shows that regional and local variations of Younger Dryas summer conditions in the North Atlantic region may have been larger than previously found from proxy data and modeling experiments.

  • 326. Bjorklund, Jesper A.
    et al.
    Gunnarson, Bjorn E.
    Krusic, Paul J.
    Grudd, Hakan
    Josefsson, Torbjörn
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ostlund, Lars
    Linderholm, Hans W.
    Advances towards improved low-frequency tree-ring reconstructions, using an updated Pinus sylvestris L. MXD network from the Scandinavian Mountains2013In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 113, no 3-4, p. 697-710Article in journal (Refereed)
    Abstract [en]

    The dendrochronological use of the parameter maximum density (MXD) in Pinus Sylvestris L., at high latitudes, has provided valuable insights into past summer temperature variations. Few long MXD chronologies, from climatically coherent regions, exist today, with the exception being in northern Europe. Five, 500-year-long, Fennoscandian, MXD chronologies were compared with regard to their common variability and climate sensitivity. They were used to test Signal-free standardization techniques, to improve inferences of low-frequency temperature variations. Climate analysis showed that, in accordance with previous studies on MXD in Fennoscandia, the summer temperature signal is robust (R (2) > 50 %) and reliable over this climatically coherent region. A combination of Individual standardization and regional curve standardization is recommended to refine long-term variability from these MXD chronologies and relieve problems arising from low replication and standardization end-effects.

  • 327. Bjorkman, Anne D.
    et al.
    Myers-Smith, Isla H.
    Elmendorf, Sarah C.
    Normand, Signe
    Rueger, Nadja
    Beck, Pieter S. A.
    Blach-Overgaard, Anne
    Blok, Daan
    Cornelissen, J. Hans C.
    Forbes, Bruce C.
    Georges, Damien
    Goetz, Scott J.
    Guay, Kevin C.
    Henry, Gregory H. R.
    HilleRisLambers, Janneke
    Hollister, Robert D.
    Karger, Dirk N.
    Kattge, Jens
    Manning, Peter
    Prevey, Janet S.
    Rixen, Christian
    Schaepman-Strub, Gabriela
    Thomas, Haydn J. D.
    Vellend, Mark
    Wilmking, Martin
    Wipf, Sonja
    Carbognani, Michele
    Hermanutz, Luise
    Levesque, Esther
    Molau, Ulf
    Petraglia, Alessandro
    Soudzilovskaia, Nadejda A.
    Spasojevic, Marko J.
    Tomaselli, Marcello
    Vowles, Tage
    Alatalo, Juha M.
    Alexander, Heather D.
    Anadon-Rosell, Alba
    Angers-Blondin, Sandra
    te Beest, Mariska
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Berner, Logan
    Bjork, Robert G.
    Buchwal, Agata
    Buras, Allan
    Christie, Katherine
    Cooper, Elisabeth J.
    Dullinger, Stefan
    Elberling, Bo
    Eskelinen, Anu
    Frei, Esther R.
    Grau, Oriol
    Grogan, Paul
    Hallinger, Martin
    Harper, Karen A.
    Heijmans, Monique M. P. D.
    Hudson, James
    Huelber, Karl
    Iturrate-Garcia, Maitane
    Iversen, Colleen M.
    Jaroszynska, Francesca
    Johnstone, Jill F.
    Jorgensen, Rasmus Halfdan
    Kaarlejärvi, Elina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klady, Rebecca
    Kuleza, Sara
    Kulonen, Aino
    Lamarque, Laurent J.
    Lantz, Trevor
    Little, Chelsea J.
    Speed, James D. M.
    Michelsen, Anders
    Milbau, Ann
    Nabe-Nielsen, Jacob
    Nielsen, Sigrid Scholer
    Ninot, Josep M.
    Oberbauer, Steven F.
    Olofsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Onipchenko, Vladimir G.
    Rumpf, Sabine B.
    Semenchuk, Philipp
    Shetti, Rohan
    Collier, Laura Siegwart
    Street, Lorna E.
    Suding, Katharine N.
    Tape, Ken D.
    Trant, Andrew
    Treier, Urs A.
    Tremblay, Jean-Pierre
    Tremblay, Maxime
    Venn, Susanna
    Weijers, Stef
    Zamin, Tara
    Boulanger-Lapointe, Noemie
    Gould, William A.
    Hik, David S.
    Hofgaard, Annika
    Jonsdottir, Ingibjorg S.
    Jorgenson, Janet
    Klein, Julia
    Magnusson, Borgthor
    Tweedie, Craig
    Wookey, Philip A.
    Bahn, Michael
    Blonder, Benjamin
    van Bodegom, Peter M.
    Bond-Lamberty, Benjamin
    Campetella, Giandiego
    Cerabolini, Bruno E. L.
    Chapin, F. Stuart, III
    Cornwell, William K.
    Craine, Joseph
    Dainese, Matteo
    de Vries, Franciska T.
    Diaz, Sandra
    Enquist, Brian J.
    Green, Walton
    Milla, Ruben
    Niinemets, Ulo
    Onoda, Yusuke
    Ordonez, Jenny C.
    Ozinga, Wim A.
    Penuelas, Josep
    Poorter, Hendrik
    Poschlod, Peter
    Reich, Peter B.
    Sande, Brody
    Schamp, Brandon
    Sheremetev, Serge
    Weiher, Evan
    Plant functional trait change across a warming tundra biome2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 562, no 7725, p. 57-+Article in journal (Refereed)
    Abstract [en]

    The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature-trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.

  • 328. Bjorkman, Anne D.
    et al.
    Myers-Smith, Isla H.
    Elmendorf, Sarah C.
    Normand, Signe
    Thomas, Haydn J. D.
    Alatalo, Juha M.
    Alexander, Heather
    Anadon-Rosell, Alba
    Angers-Blondin, Sandra
    Bai, Yang
    Baruah, Gaurav
    te Beest, Mariska
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Environmental Sciences, Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, The Netherlands.
    Berner, Logan
    Bjork, Robert G.
    Blok, Daan
    Bruelheide, Helge
    Buchwal, Agata
    Buras, Allan
    Carbognani, Michele
    Christie, Katherine
    Collier, Laura S.
    Cooper, Elisabeth J.
    Cornelissen, J. Hans C.
    Dickinson, Katharine J. M.
    Dullinger, Stefan
    Elberling, Bo
    Eskelinen, Anu
    Forbes, Bruce C.
    Frei, Esther R.
    Iturrate-Garcia, Maitane
    Good, Megan K.
    Grau, Oriol
    Green, Peter
    Greve, Michelle
    Grogan, Paul
    Haider, Sylvia
    Hajek, Tomas
    Hallinger, Martin
    Happonen, Konsta
    Harper, Karen A.
    Heijmans, Monique M. P. D.
    Henry, Gregory H. R.
    Hermanutz, Luise
    Hewitt, Rebecca E.
    Hollister, Robert D.
    Hudson, James
    Huelber, Karl
    Iversen, Colleen M.
    Jaroszynska, Francesca
    Jimenez-Alfaro, Borja
    Johnstone, Jill
    Jorgensen, Rasmus Halfdan
    Kaarlejarvi, Elina
    Klady, Rebecca
    Klimesova, Jitka
    Korsten, Annika
    Kuleza, Sara
    Kulonen, Aino
    Lamarque, Laurent J.
    Lantz, Trevor
    Lavalle, Amanda
    Lembrechts, Jonas J.
    Levesque, Esther
    Little, Chelsea J.
    Luoto, Miska
    Macek, Petr
    Mack, Michelle C.
    Mathakutha, Rabia
    Michelsen, Anders
    Milbau, Ann
    Molau, Ulf
    Morgan, John W.
    Morsdorf, Martin Alfons
    Nabe-Nielsen, Jacob
    Nielsen, Sigrid Scholer
    Ninot, Josep M.
    Oberbauer, Steven F.
    Olofsson, Johan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Onipchenko, Vladimir G.
    Petraglia, Alessandro
    Pickering, Catherine
    Prevey, Janet S.
    Rixen, Christian
    Rumpf, Sabine B.
    Schaepman-Strub, Gabriela
    Semenchuk, Philipp
    Shetti, Rohan
    Soudzilovskaia, Nadejda A.
    Spasojevic, Marko J.
    Speed, James David Mervyn
    Street, Lorna E.
    Suding, Katharine
    Tape, Ken D.
    Tomaselli, Marcello
    Trant, Andrew
    Treier, Urs A.
    Tremblay, Jean-Pierre
    Tremblay, Maxime
    Venn, Susanna
    Virkkala, Anna-Maria
    Vowles, Tage
    Weijers, Stef
    Wilmking, Martin
    Wipf, Sonja
    Zamin, Tara
    Tundra Trait Team: a database of plant traits spanning the tundra biome2018In: Global Ecology and Biogeography, ISSN 1466-822X, E-ISSN 1466-8238, Vol. 27, no 12, p. 1402-1411Article in journal (Refereed)
    Abstract [en]

    Motivation: The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade‐offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite data, and to inform Earth system model parameters.

    Main types of variable contained: The database contains 91,970 measurements of 18 plant traits. The most frequently measured traits (> 1,000 observations each) include plant height, leaf area, specific leaf area, leaf fresh and dry mass, leaf dry matter content, leaf nitrogen, carbon and phosphorus content, leaf C:N and N:P, seed mass, and stem specific density.

    Spatial location and grain: Measurements were collected in tundra habitats in both the Northern and Southern Hemispheres, including Arctic sites in Alaska, Canada, Greenland, Fennoscandia and Siberia, alpine sites in the European Alps, Colorado Rockies, Caucasus, Ural Mountains, Pyrenees, Australian Alps, and Central Otago Mountains (New Zealand), and sub‐Antarctic Marion Island. More than 99% of observations are georeferenced.

    Time period and grain: All data were collected between 1964 and 2018. A small number of sites have repeated trait measurements at two or more time periods.

    Major taxa and level of measurement: Trait measurements were made on 978 terrestrial vascular plant species growing in tundra habitats. Most observations are on individuals (86%), while the remainder represent plot or site means or maximums per species.

    Software format: csv file and GitHub repository with data cleaning scripts in R; contribution to TRY plant trait database (www.try-db.org) to be included in the next version release.

  • 329. Björck, S
    et al.
    Rittenoura, T
    Rosén, P
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Franca, Z
    Möller, P
    Snowball, I
    Wastegård, S
    Bennike, O
    Kromer, B
    A Holocene lacustrine record in the central North Atlantic: proxies for volcanic activity, short-term NAO mode variability, and long-term precipitation changes2006In: Quaternary Science Reviews, Vol. 25, p. 9-32Article in journal (Refereed)
  • 330.
    Björk Berggren, Karin
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Hurtig, Malin
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Egenkontrollprogram för små livsmedelsföretagare: - Vad krävs för de skall ska uppnå livsmedelslagstiftningens krav?2005Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 331. Björk, G
    et al.
    Nohr, C
    Gustafsson, BG
    Lindberg, Amund E. B.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ice dynamics in the Bothnian Bay inferred from ADCP measurements2008In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 60, no 1, p. 178-188Article in journal (Refereed)
    Abstract [en]

    A bottom mounted ADCP has monitored the ice motion and thickness in Bothnian Bay, Baltic Sea during the entire winter season 2004. The ADCP was deployed at 20 m depth at Falkensgrund well outside the land fast ice zone. The data shows that the ice motion is primarily driven by the wind but with a clear influence of internal ice stresses. The ice stresses become more dominant as the ice grow thicker with increasing number of observations with nearly stationary ice for relatively high wind speeds. A clear dependence of the ice/wind speed ratio to wind shifts is detected with higher ratio in the new wind direction. The effect of strain hardening is also seen in several events as decreasing ice speed, sometimes to zero, in spite of constant wind speed and wind direction. A rough force balance computation gives a compressive ice strength of about  9 × 104 N m−2 , which is much larger than normally used in numerical ice models. The ice thickness data show numerous ice ridges with ice draft well above 1 m passing the instrument. The ridges make up a large portion, 30–50%, of the total ice volume showing that dynamical processes are important for the total ice production in the Bothnian Bay.

  • 332.
    Björk, Johanna
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Fungerar utbildningen i livsmedelshygien hos verksamhetsutövare vid Linköpings och Umeå universitet2007Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 333. Björk, R G
    et al.
    Klemendtsson, L
    Molau, Ulf
    Harndorf, J
    Ödman, A
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Linkages between N turnover and plant community structure in a tundra landscape2007In: Plant and Soil, Vol. 294, p. 247-261Article in journal (Refereed)
  • 334.
    Björkman, Andreas
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Olja i överskottsvatten: föroreningssituation och förbättringsmöjligheter vid LKAB i Malmberget2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 335.
    Björkman, Andreas
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Olja i överskottsvatten: Föroreningssituationen och förbättringsmöjligheter vid LKAB Malmberget2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 336.
    Björkman, Joanna
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Utsläpp av Flyktiga Organiska Föreningar och Partiklar i Falun: Trafiken och industrins bidrag av PM10 och VOC2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Emissions from Particles and Volatile Organic Compounds (VOC) in Falun.-How is the emission divided between particles and VOC?

    This study investigates the air quality in Falun, a small city in central Sweden, with a focus on particles and volatile organic compounds (VOC). Falun is located in a valley which makes it sensitive to inversions, when the vertical mixing of air over the city is prevented. When this happens emissions over the city can stay for days and the pollution levels can be high. The report is based upon a literature review, calculation of emissions from traffic and a survey of industrial emissions. Emission of VOCs can be dangerous to people and contributes to the production of ground- level ozone. Particles can be a carrier for other dangerous compounds. The result shows that high pollution levels caused by inversions can happen. The temperature, wind and temperature differences show that inversions during the winter months are possible up to half of the time. Emissions from cars and industries are a problem. The municipality forced to control air pollution and in Swedish law there is a threshold value for both particles and the volatile organic compounds benzene. Spreading of pollution in air in Falun is centered around the emission sourses. Because it´s hard to prevent inversions, the municipality must focus on reducing emission of pollutants. This can be done through road planning and diverting traffic to other routes around the city.

  • 337.
    Björkman, Sarah
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Styrande faktorer vid konsumtion av griskött: En studie bland konsumenter i Umeå kommun2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Influencing factors inthe consumption of pork - a study of consumers in the municipality of Umeå

    This report examines how the current situation regarding porkconsumption looks in Umeå. The survey was based on the current reduction ofSwedish pig producers. This is assumed to be due to high animal welfarestandards in Sweden andtherefore higher costs including construction of stall spaces than Denmark. Acomparison between Sweden’sand Denmark'sanimal welfare legislation and its requirements for pigs were done toinvestigate whether there were differences in space requirements and noiserequirements. The results showed that the Swedish standards requirements forspaces for growing pigs and boars were bigger than the Danish measurementrequirements. Also noise requirements were higher in Sweden. Furthermore, the surveyquestionnaires were distributed to residents in the municipalityof Umeå to investigate whether theimage of the increased consumption of imported pork is consistent with all of Sweden. Questionsasked was which factors influence their choice of pork for consumption, ifanimal welfare legislative requirements have played a part in the election, ifthey could feel misled about the origin label by country of origin was missingon the package. Differences in regulatory requirements for dimensions and noiselevel may allow the Swedish pork to be more expensive. Consumers were in favourof Swedish pork, but in the end it was probably the price that influences thechoice of pork in consumption. Consumers also felt that the absence of anorigin of pork can be a misleading factor in consumption that leads to importedpork is consumed instead of Swedish pork.

  • 338. Björkvald, L
    et al.
    Borg, H
    Laudon, Hjalmar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Mörth, C M
    Influence of landscape type on trace metals in small boreal catchments2007In: Geochimica et Cosmochimica Acta, Vol. 71, p. A95-A95 Suppl. SArticle in journal (Refereed)
  • 339. Björkvald, L.
    et al.
    Buffam, I.
    Laudon, Hjalmar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Mörth, C.M.
    Hydrogeochemistry of Fe and Mn in small boreal streams: The role of seasonality, landscape type and scale2008In: Geochimica et Cosmochimica Acta, Vol. 72, no 12, p. 2789-2804Article in journal (Refereed)
    Abstract [en]

    Stream water from a stream network of 15 small boreal catchments (0.03-67 km(2)) in northern Sweden was analyzed for unfiltered (total) and filtered (< 0.4 mu m) concentrations of iron (Fe-tot and Fe-< 0.4) and manganese (Mn-tot and Mn < 0.4). The purpose was to investigate the temporal and spatial dynamics of Fe, Mn and dissolved organic carbon (DOC) as influenced by snow melt driven spring floods and landscape properties, in particular the proportion of wetland area. During spring flood, concentrations of Fetot, Fe-< 0.4, Mn-tot, Mn-< 0.4 and DOC increased in streams with forested catchments (< 2% wetland area). In catchments with high coverage of wetlands (> 30% wetland area) the opposite behavior was observed. The hydrogeochemistry of Fe was highly dependent on wetlands as shown by the strong positive correlation of the Fe-tot/Al-tot ratio with wetland coverage (r(2) = 0.89,p < 0.001). Furthermore, PCA analysis showed that at base flow Fe-tot and Fe-< 0.4 were positively associated with wetlands and DOC, whereas they were not associated during peak flow at spring flood. The temporal variation of Fe was likely related to varying hydrological pathways. At peak discharge Fetot was associated with variables like silt coverage, which highlights the importance of particulates during high discharge events. For Mn there was no significant correlation with wetlands, instead, PCA analysis showed that during spring flood Mn was apparently more dependent on the supply of minerogenic particulates from silt deposits on the stream banks of some of the streams. The influence of minerogenic particulates on the concentration of, in particular, Mn was greatest in the larger, lower gradient streams, characterized by silt deposits in the near-stream zone. In the small forested streams underlain by till, DOC was of greater importance for the observed concentrations, as indicated by the positive correlation of both Fe-tot and Fe-< 0.4 with DOC (r(2) = 0.77 and r(2) = 0.76, p < 0.001) at the smallest headwater forest site. In conclusion, wetland area and DOC were important for Fe concentrations in this boreal stream network, whereas silt deposits strongly influenced Mn concentrations. This study highlights the importance of studying stream water chemistry from a landscape perspective in order to address future environmental issues concerning mobility of Fe, Mn and associated trace metals. (c) 2008 Elsevier Ltd. All rights reserved.

  • 340. Björkvald, L
    et al.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Laudon, Hjalmar
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Humborg, C
    Mörth, C-M
    Landscape variations in stream water SO4 and d34S-SO4 in a boreal stream network2009In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, p. 4648-4660Article in journal (Refereed)
    Abstract [en]

    Despite reduced anthropogenic deposition during the last decades, deposition sulphate may still play an important role in the biogeochemical cycles of S and many catchments may act as net sources of S that may remain for several decades. The aim of this study is to elucidate the temporal and spatial dynamics of both SO42− and δ34SSO4 in stream water from catchments with varying percentage of wetland and forest coverage and to determine their relative importance for catchment losses of S. Stream water samples were collected from 15 subcatchments ranging in size from 3 to 6780 ha, in a boreal stream network, northern Sweden. In forested catchments (<2% wetland cover) S–SO42− concentrations in stream water averaged 1.7 mg L−1 whereas in wetland dominated catchments (>30% wetland cover) the concentrations averaged 0.3 mg L−1. A significant negative relationship was observed between S–SO42− and percentage wetland coverage (r2 = 0.77, p < 0.001) and the annual export of stream water SO42− and wetland coverage (r2 = 0.76, p < 0.001). The percentage forest coverage was on the other hand positively related to stream water SO42− concentrations and the annual export of stream water SO42− (r2 = 0.77 and r2 = 0.79, respectively). The annual average δ34SSO4 value in wetland dominated streams was +7.6‰ and in streams of forested catchments +6.7‰. At spring flood the δ34SSO4 values decreased in all streams by 1‰ to 5‰. The δ34SSO4 values in all streams were higher than the δ34SSO4 value of +4.7‰ in precipitation (snow). The export of S ranged from 0.5 kg S ha−1 yr−1 (wetland headwater stream) to 3.8 kg S ha−1 yr−1 (forested headwater stream). With an average S deposition in open field of 1.3 kg S ha−1 yr−1 (2002–2006) the mass balance results in a net export of S from all catchments, except in catchments with >30% wetland. The high temporal and spatial resolution of this study demonstrates that the reducing environments of wetlands play a key role for the biogeochemistry of S in boreal landscapes and are net sinks of S. Forested areas, on the other hand were net sources of S.

  • 341. Blackburn, M.
    et al.
    Ledesma, Jose L. J.
    Näsholm, Torgny
    Laudon, Hjalmar
    Sponseller, Ryan A.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment2017In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 122, no 2, p. 324-339Article in journal (Refereed)
    Abstract [en]

    Catchment science has long held that the chemistry of small streams reflects the landscapes they drain. However, understanding the contribution of different landscape units to stream chemistry remains a challenge which frequently limits our understanding of export dynamics. For limiting nutrients such as nitrogen (N), an implicit assumption is that the most spatially extensive landscape units (e.g., uplands) act as the primary sources to surface waters, while near-stream zones function more often as sinks. These assumptions, based largely on studies in high-gradient systems or in regions with elevated inputs of anthropogenic N, may not apply to low-gradient, nutrient-poor, and peat-rich catchments characteristic of many northern ecosystems. We quantified patterns of N mobilization along a hillslope transect in a northern boreal catchment to assess the extent to which organic matter-rich riparian soils regulate the flux of N to streams. Contrary to the prevailing view of riparian functioning, we found that near-stream, organic soils supported concentrations and fluxes of ammonium (NH4+) and dissolved organic nitrogen that were much higher than the contributing upslope forest soils. These results suggest that stream N chemistry is connected to N mobilization and mineralization within the riparian zone rather than the wider landscape. Results further suggest that water table fluctuation in near-surface riparian soils may promote elevated rates of net N mineralization in these landscapes.

  • 342. Blanchet, Guillaume
    et al.
    Gavazov, Konstantin
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Bragazza, Luca
    Sinaj, Sokrat
    Responses of soil properties and crop yields to different inorganic and organic amendments in a Swiss conventional farming system2016In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 230, p. 116-126Article in journal (Refereed)
    Abstract [en]

    In agro-ecosystems, fertilization practices are crucial for sustaining crop productivity. Here, based on a 50-year long-term experiment, we studied the influence of fertilization practices (inorganic and/or organic) and nitrogen (N) application rates on (i) soil physicochemical properties, (ii) microbial and earthworm communities and (iii) crop production. Our results showed that soil organic carbon content was increased by incorporation of crop residues (+2.45%) and farmyard manure application (+6.40%) in comparison to the use of mineral fertilizer alone. In contrast, soil carbon stock was not significantly affected by these fertilization practices. Overall, only farmyard manure application improved soil physicochemical properties compared to mineral fertilization alone. Soil microbial population was enhanced by the application of organic amendments as indicated by microbial biomass and phospholipid-derived fatty acids contents. The fertilization practices and the N application rates affected significantly both the biomass and composition of earthworm populations, especially the epigeic and endogeic species. Finally, farmyard manure application significantly increased crop yield (+3.5%) in comparison to mineral fertilization alone. Crop residue incorporation rendered variable but similar crop yields over the 50-year period. The results of this long-term experiment indicate that the use of organic amendments not only reduces the need for higher amount of mineral N fertilizer but also improves the soil biological properties with direct effects on crop yield.

  • 343.
    Blank, Erika
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Systematiskt arbete med hälsa och säkerhet på en alpinskidanläggning2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    All Swedish companies are, according to The Work Environment Act, required to have asystematic work environment management (SWEM). This report studies the SWEM of a skiresort, in order to investigate whether all requirements in the provision are met or whether thecompany need to improve their work. This investigation was based on interviews andobservations on how management of the work environment is handled in the company atpresent. The aim is to create a foundation for a systematic management, helping the companyto improve its work environment management. The risks in the work environment wereinvestigated, assessed and categorized from A to D according to probability andconsequences. Measures to reduce or eliminate risks are suggested and measures which arenot taken immediately are noted in an action plan. 19 risks were found, eight were categorizedas B and eleven as C. The company fulfils the legislative requirements in two areas,distribution of assignments and follow up on SWEM. In two areas the requirements are notmet at all, having an action plan and occupational health services. In six areas more work isneeded. Most shortcomings are in reference to documentation of SWEM, but also knowledge.Knowledge is not taken charge of and new employees are not given as good introduction asthe company is able to. In spite of the lack of adhering fully to legislation, the company isheading towards a complete SWEM. The areas with a total shortcoming are few, while theareas with an ongoing work are several.

  • 344. Blaser, Wilma J.
    et al.
    Sitters, Judith
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Hart, Simon P.
    Edwards, Peter J.
    Venterink, Harry Olde
    Facilitative or competitive effects of woody plants on understorey vegetation depend on N-fixation, canopy shape and rainfall2013In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 101, no 6, p. 1598-1603Article in journal (Refereed)
    Abstract [en]

    A recent meta-analysis suggested that differences in rainfall are a cause of variation in tree-grass interactions in savannas, with trees facilitating growth of understorey grasses in low-rainfall areas, but competing with them under higher rainfall. We hypothesized that this effect of rainfall upon understorey productivity is modified by differences in the growth form of the woody plants (i.e. the height of the lower canopy) or by their capacity to fix nitrogen. We performed a meta-analysis of the effects of woody plants on understorey productivity, incorporating canopy height and N-fixation, and their interaction with rainfall. N-fixing woody plants enhanced understorey productivity, whereas non-fixers had a neutral or negative effect, depending on high or low canopy, respectively. We found a strong negative correlation between rainfall and the degree to which trees enhanced understorey productivity, but only for trees with a high canopy.Synthesis. The effect of woody plants on understorey productivity depends not only on rainfall, but also on their growth form and their capacity to fix N. Facilitation occurs mostly when woody plants ameliorate both water and nitrogen conditions. However, a low canopy suppresses understorey vegetation by competing for light, regardless of water and nutrient relations.

  • 345. Blass , Alex
    et al.
    Bigler, Christian
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Grosjean, Martin
    Sturm, Michael
    Decadal-scale autumn temperature reconstruction back to AD 1580 inferred from the varved sediments of Lake Silvaplana (southeastern Swiss Alps)2007In: Quaternary Research, ISSN 0033-5894, E-ISSN 1096-0287, Vol. 68, no 2, p. 184-195Article in journal (Refereed)
    Abstract [en]

    A quantitative high-resolution autumn (September-November) temperature reconstruction for the southeastern Swiss Alps back to AD 1580 is presented here. We used the annually resolved biogenic silica (diatoms) flux derived from the accurately dated and annually sampled sediments of Lake Silvaplana (46°27'N, 9°48'E, 1800 m a.s.1.). The biogenic silica flux smoothed by means of a 9-yr running mean was calibrated (r=0.70, p<0.01) against local instrumental temperature data (AD 1864-1949). The resulting reconstruction (±2 standard errors=±0.7 °C) indicates that autumns during the late Little Ice Age were generally cooler than they were during the 20th century. During the cold anomaly around AD 1600 and during the Maunder Minimum, however, the reconstructed autumn temperatures did not experience strong negative departures from the 20th-century mean. The warmest autumns prior to 1900 occurred around AD 1770 and 1820 (0.75 °C above the 20th-century mean). Our data agree closely with two other autumn temperature reconstructions for the Alps and for Europe that are based on documentary evidence and are completely unrelated to our data, revealing a very consistent picture over the centuries.

  • 346. Blenckner, Thorsten
    et al.
    Österblom, Henrik
    Larsson, Per
    Andersson, Agneta
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Elmgren, Ragnar
    Baltic Sea ecosystem-based management under climate change: Synthesis and future challenges2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, no Suppl 3, p. S507-S515Article in journal (Refereed)
    Abstract [en]

    Ecosystem-based management (EBM) has emerged as the generally agreed strategy for managing ecosystems, with humans as integral parts of the managed system. Human activities have substantial effects on marine ecosystems, through overfishing, eutrophication, toxic pollution, habitat destruction, and climate change. It is important to advance the scientific knowledge of the cumulative, integrative, and interacting effects of these diverse activities, to support effective implementation of EBM. Based on contributions to this special issue of AMBIO, we synthesize the scientific findings into four components: pollution and legal frameworks, ecosystem processes, scale-dependent effects, and innovative tools and methods. We conclude with challenges for the future, and identify the next steps needed for successful implementation of EBM in general and specifically for the Baltic Sea.

  • 347.
    Blind, Caroline
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Tungmetallen krom: En studie av dess miljöeffekter i samband med läderproduktion och avfallshantering2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 348.
    Blochel, Alexander
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Factors influencing ground lichen height in the Boreal-zone: The effects of reindeer husbandry and forestry industries in northern Sweden2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There are indications that lichen-rich areas in northern Sweden, commonly used for winter grazing by semi-domesticated reindeer (Rangifer tarandus), has declined by 30-50% since the 1950s. This is mainly believed to be because of a rise in clear-cutting activities during that time period. With fewer areas for the reindeer to conduct their winter grazing it is important to know how grazing activities potentially affect the ground lichen. This report investigates what variables, such as tree density and reindeer grazing intensity, affect the height of five ground lichens; four Cladonia and one Cetraria species. The research was conducted in Norrbotten and Västerbotten, with a total of 55 sample plots, during the month of July 2015. Previous National Forest Inventory plots with a ground cover of at least 25% reindeer lichen were used. The commonly found species were Cladonia rangiferina and Cladonia arbuscula/mitis. Grazing intensity from reindeer had a low explanatory power on the variation in the mat-forming lichen height in boreal forests if considered by itself (R2=0.05, p=0.06). Instead, reindeer grazing effects became more evident when considering an interaction with the tree density of the forest. Tree density and grazing pressure have an important role for lichen height, but there probably are more variables which, directly or indirectly, affect lichen height. Tree density also effects the amount of reindeer found in the area and seems to be of great importance when reindeer graze during the winter.

  • 349.
    Blochel, Alexander
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Population demography’s potential effect on stoichiometry: Assessing the growth rate hypothesis with demography2017Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    The elemental composition within structured insect populations was tested by creating a new method to analyze how variables (survival, growth and fecundity) within a population matrix could potentially affect the stoichiometric regime of a structured population at steady state. This was done by focusing on if the growth rate hypothesis, which states that there is a linear relationship between an individual growth rate and the percent of phosphorus within the individual, works at a population level. This was analyzed by creating and combining two matrices: the matrix-population containing the variables and a matrix containing the element phosphorus and dry weight. Data from a beetle species, Chrysomela tremulae F., was used as a guideline to create eight stoichiometric generic populations, where survival, growth and fecundity were tested in each of the eight generic populations. The results showed deviations from the growth rate hypothesis, suggesting that the hypothesis does not always work within structured populations. However, more research is needed to predict exactly how this hypothesis works in populations. Overall, this new method for analyzing stoichiometry within structured populations is a useful analytical tool, but there is a need for analyzing the results from these models in a more efficient way.

  • 350. Block, Benjamin D.
    et al.
    Denfeld, Blaize A.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Stockwell, Jason D.
    Flaim, Giovanna
    Grossart, Hans-Peter F.
    Knoll, Lesley B.
    Maier, Dominique B.
    North, Rebecca L.
    Rautio, Milla
    Rusak, James A.
    Sadro, Steve
    Weyhenmeyer, Gesa A.
    Bramburger, Andrew J.
    Branstrator, Donn K.
    Salonen, Kalevi
    Hampton, Stephanie E.
    The unique methodological challenges of winter limnology2019In: Limnology and Oceanography: Methods, ISSN 1541-5856, E-ISSN 1541-5856, Vol. 17, no 1, p. 42-57Article, review/survey (Refereed)
    Abstract [en]

    Winter is an important season for many limnological processes, which can range from biogeochemical transformations to ecological interactions. Interest in the structure and function of lake ecosystems under ice is on the rise. Although limnologists working at polar latitudes have a long history of winter work, the required knowledge to successfully sample under winter conditions is not widely available and relatively few limnologists receive formal training. In particular, the deployment and operation of equipment in below 0 degrees C temperatures pose considerable logistical and methodological challenges, as do the safety risks of sampling during the ice-covered period. Here, we consolidate information on winter lake sampling and describe effective methods to measure physical, chemical, and biological variables in and under ice. We describe variation in snow and ice conditions and discuss implications for sampling logistics and safety. We outline commonly encountered methodological challenges and make recommendations for best practices to maximize safety and efficiency when sampling through ice or deploying instruments in ice-covered lakes. Application of such practices over a broad range of ice-covered lakes will contribute to a better understanding of the factors that regulate lakes during winter and how winter conditions affect the subsequent ice-free period.

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